Hi,
I have put up on Sourceforge - radxazero3e-air-gapped scripts to set up a Radxa Zero 3E as an air-gapped password and security token manager, and as a store of sensitive information. It also has an encrypted root partition.
If you go to the [Files] tab, the README.md (displayed automatically) gives much more details.
Note - all files in the ‘tar.xz’ are text, with a lot of bash scripts, gawk scripts, sed scripts, etc…
There is also art work for an acrylic frame for a 7" touch screen.